1. Technology Field
The present invention generally relates to a data protecting method, and more particularly, to a data protecting method for a rewritable non-volatile memory module, a memory controller, and a memory storage device.
2. Description of Related Art
Along with the widespread of digital cameras, cell phones, and MP3 players in recently years, the consumers' demand to storage media has increased drastically. Rewritable non-volatile memory (for example, flash memory) is one of the most adaptable storage media to aforementioned portable multimedia devices due to its many characteristics such as data non-volatility, low power consumption, small volume, and non-mechanical structure.
In a multi level cell (MLC) NAND flash memory module, each physical erasing unit includes a plurality of physical programming units, and these physical programming units are categorized into lower physical programming units and upper physical programming units. If a system error occurs when an upper physical programming unit is programmed, an error may be produced in the data in the lower physical programming unit corresponding to the same word line. Besides, when data is written, the lower physical programming units have to be programmed before the upper physical programming units are programmed. A host system may write data into a rewritable non-volatile memory module through write commands. The host system may also issue a flush command to clear data within a logical range, so that the data is not stored in a volatile memory. Generally, the cleared data is written into the rewritable non-volatile memory module, and the host system considers that data before the flush command is issued has been completely and safely written. However, if data is written into a lower physical programming unit before the host system issues the flush command and the upper physical programming unit corresponding to the same word line is programmed and a system error occurs after the host system issues the flush command, an error may be produced in the data in the lower physical programming unit. Thereby, how to protect the data has become a major subject in the industry.
Nothing herein should be construed as an admission of knowledge in the prior art of any portion of the present invention. Furthermore, citation or identification of any document in this application is not an admission that such document is available as prior art to the present invention, or that any reference forms a part of the common general knowledge in the art.